SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29a1ab5ed8bb65cad18e6d6d62807f873606cd9bc8ac553bb1b6f33c45f48143' 
  AND token = 'BbXyzi/h5FKq9leu8vFc5J7wDni4LRrYiqVY7NAQUHE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}